Electric lamp and mounting



F. E, CARLSON 2,300,870 ELECTRIC LAMP AND MOUNTING Nov. 3', 1942.

Filed ma 17, 1941 Figl,

lnvn'tor Frank E. Carlson I M fin/ His A ttorneg.

Patented Nov. 3, 1942 UNITED STATE ELECTRIC LAMP AND MOUNTING Frank E. Carlson, East Cleveland, Ohio, assignor to GeneralElectric Company, a corporation of J New York Application May 17, 1941, SerialNo. 393,924

7 Claims. (01. 176-32) My invention relatesfin general'to bases and mountings for electric lamps, and is particularly applicable to prefocused electric lamps which are adapted to be inserted, bulb. first, intothe lamp socket or mounting. H i

In certain types of motion picture projectors in use at present, the electric incandescentlamp constituting the light source. for the projector is assembled in place within the :projectorlamp housing by inserting the lamp; bulb first, through any opening in the bottom ofrthe housing, the lamp being held in place in the. housing by means of a bottom closure cap threaded into the said opening at the bottom of the housing. To position the lamp in a predetermined position within the lamp housing, a prefocusing arrangement is employed which comprises an inwardly projecting positioning ring or collar within the lamp housing having a slot therein, and a laterally extending flange onthe lamp base adapted to engage the under surface of the collarand provided with an upwardly extending lug adapted to enter the slot in the collar. so as, to position the lamp in a predetermined position angularly of its axis. With such an arrangement, it is unnecessary to have access into the bulb chamber of the lamp housing for lamp installation or removal purposes; and itis not necessary to grasp the body of the lamp in the installation or. removal of the lamp. i i

I-Ieretofore, the assembly of the electric lamp in such projector lamp housings has been more or less diificult and inconvenient because of, the necessity for manually holding the lampup within the lamp housing with the upwardly extending positioning lug on the lamp base engaged within the slot in the positioning collar, and then quickly retracting the hand and immediately positioning thebottom closure cap underneath the lamp before the lamp can drop out of the housing or drop to the point where the upstanding lug on the, lamp base is withdrawnfrom the slot in the positioning collari One object of my invention. is to provide an electric lamp and socket arrangement which facilitates the installation and removal of the lamp through the bottom of the socket and which provides an accurate positioning of the lamp within the socket. l i 1 Another object of my invention is to provide, in an electric lamp and socket arrangement permitting installation and removal of the lamp lamp within the socket prior to the application of 55 the final lamp support means to the lamp socket. A feature of the invention is the provision of lug means onthe lamp base which is adaptedto entera slot in a lamp positioning collar disposed. within the lamp socket and. which is further adapted to engage and rest on the top surface of the said lamp positioning collar to thereby support the lamp in, and prevent the same from dropping out of the socket. Further objects and advantages of my inyention will appear from the following description of species thereof. and from the accompanying drawing, in whiehr i N Fig. 1 is a vertical section of the lamp housing of a motion picture projector equipped with a lamp and socket according to my invention; Fi 2 is a fragmentary view, partly in section, ofthe lamp and socket shown in Fig. 1 with the lamp shown at an intermediate stage of its assembly within the socket; Fig. 3 is a perspective View of the prefocusinglamp collar with which the lamp shown in Figs. 1 and 2 is provided; Figs. 4 and 5 are perspective views of two modified forms oi prefocusing collars comprising my invention; and Fig.6 is an end view of the base end of the lamp shownin Figs. 1 and 2. j Referring to the drawing, an electric incandescent lamp III is shown mounted in place within a vertical cylindrical lamp housing or casing II comprising a metallic upper main portion l2 and a lower socket portion 13 consisting of a body of suitable molded insulating material secured to the bottom of the main casing portion [2 in any suitable manner, such as by screws 28. The insulating body or socket portion l3 has a relatively large vertical bore I4 therethrough communicating with thehollow interior of the upper main lamp housing I2. Molded in the socket body l3 coaxial with the bore l4 therein and intermediate the top and bottom of the body is a metallic positioning collar or ring l5 which projects inwardly from the surface of the bore I4 and forms a downwardly facingannular contact and positioning surface It. likewise molded in the socket body [3 coaxial with the bore I4 therein, and disposed below the ring [5 andlin sulated therefrom, is a cylindrical internally screw-threaded metallic conductor member or sleeve l1. Removably secured to the bottom of the socket body I3 so as to close ofi the bottom of the bore I4 is a closure cap l8 comprising an upwardly facing cup-shaped metallic member l5, externally screw-threaded for threaded engagement with the conductor member I 1, and a cover member 20 of suitable insulatingmaterial sew cured to the exterior surface of the metal cup member I9 and provided with a hand knob 2| for convenient insertion and removal of the closure cap. Secured to the upper surface of the metal cup member I9 is a spring contact blade 22 the free end of which is disposed centrally of the member I9 so as to engage the bottom end contact 23 of the lamp It.

The ring I and the sleeve member II are provided with lateral extensions or lugs 24 which extend through the wall of the socket body I3 to externally exposed points within recesses 25 formed in the body. The said extensions or lugs 24 form the terminals of the lamp, socket to which are attached wires 26, from a source of current, by conventional headed screws '21 screwthreaded into the lugs 24.

The bore I4 in the socket body I3 and the coaxial openings in the ring I5 and sleeve member I! are formed of sufflcient size to permit the bulb 29 of the electric incandescent lamp ID to be passed upwardly through the socket bore I4 and the said openings in the ring and sleeve members I5 and I I into the position shown in Fig. 1 wherein the bulb 29 is disposed within the main lamp housing I2. The lamp I0 comprises, in addition to the bulb 29, a. concentrated filament 3|! mounted with the bulb and a conventional lamp base 3| secured to the lower end of the bulb and comprising a cylindrical metallic shell portion 32 and the aforementioned bottom end contact 23 separated by suitable insulation 33. Fitted over the shell 32 of the lamp base and secured thereto in any suitable manner, such as by soldering, is a metallic prefocusing contact collar or adapter 34 comprising laterally projecting flange means preferably in the form of a circumferential flange 35 disposed substantially normal to the axis of the lamp, and a sleeve or band portion 36 extending upwardly from the inner edge or periphery of the flange 35. The said flange extends laterally beyond the side wall of the lamp bulb 29 and is provided with a flat upwardly facing contact surface 31 which engages the downwardly facing flat contact surface IB of the ring I5 when the lamp I0 is properly mounted within the socket. Obviously, the laterally projecting flange means 35 need not be formed as a continuous circumferential flange but may be divided instead into a plurality of laterally extending lugs or wings, preferably three or more in number. In addition, the socket ring engaging portions of the flange may be formed of three or more raised protuberances or bosses defining a plane, instead of a flat upwardly facing surface. The sleeve or band 36 of the adapter may, of course, be omitted and the flange 35 used alone as a flat ring, or the said flange may be incorporated in the base shell 32 itself.

When the lamp I0 is inserted in the lamp housing II and the bottom closure cap I8 is threaded into place in the socket body I3, the spring contact 22 engages the bottom end contact 23 of the lamp base and forces-the lamp up so that the upper surface 31 of the flange 35 is firmly pressed against the under surface I6 of the ring I5. The prefocusing collar 34 is secured to the lamp base 3| with the plane of the upper surface 31 of the flange 35 located in a predetermined position longitudinally and transversely with respect to the lamp filament so that when the lamp is mounted in place within the socket, with the upper-surface 3'! of the flange in engagement with the under-surface of the ring I5, the filament 30 will be located in a predetermined position within the lamp chamber II whereby it is positioned in proper alignment with the optical system of the projector.

The filament 30 of the lamp is of the planar type, such as the conventional monoplane on biplane type used in projection lamps. The filament shown in the drawing, however, is of the monoplane type. To position the planar filament 30 of the lamp in a predetermined position angularly of the lamp axis, the prefocusing collar or adapter 34 is provided with a positioning lug 38 extending laterally outward from the sleeve portion 36 of the collar closely adjacent the flange 35 and adapted to enter a slot 33 in the positioning ring and engage one of the side walls 40 (Fig. 2) of such slot, 1. e., that wall towards which the lug is apt to be moved by the rotational movement imparted to the lamp by the turning action of the closure cap I8 as it is threaded into place within the socket body I3. The positioning lug 38 is preferably punched or cut out of the sleeve portion 36 of the prefocusing collar; but it may be formed instead of a separate member which is secured either to the said sleeve portion 36 or the positioning flange 31 of the prefocusing collar.

I-Ieretofore, in assembling lamps of the above described construction in the socket I3, it has been necessary to manually support the lamp up within the lamp chamber with the positioning lug 38 disposed within the slot 39 in the positioning ring I5, and then to quickly withdraw the manual support of the lamp and position the bottom closure cap underneath the lamp before the lamp could drop out of the socket or drop down a sufficient distance to allow the positioning lug 38 to become disengaged from the slot 39. Such an operation is more or less inconvenient and is apt to result in the accidental'dropping out and breakage of the lamp.

In accordance withthe invention, I have provided preliminary or temporary supporting means for the lamp which functions to facilitate assembly of the lamp within the socket by positively supporting the lamp up within the lamp chamber so as to prevent the accidental dropping out of the lamp during the installation or removal of the same. The said temporary supporting means comprises a horizontally extending projection or lip 4| formed at the upper edge of the positioning lug 38 and extending therefrom in a direction tangential to the'cylindrical sleeve portion 36 of the prefocusing collar 34. The said projection 4| provides a downwardly facing engagement surface which is adapted to rest on the upper surface of the positioning ring I5 tothereby temporarily support the lamp within the socket whenever the bottom closure cap I8 is not in place in the socket body I3. The overall circumferential width of the positioning lug 38 and its projecting lip 4| is made slightly less than the width of the ring slot 39 so that the'lug, with its projecting lip 4|, can freely pass through the said slot. The projecting lip 4| preferably extends from that side of the lug 38 which is to engage the shoulder or wall 40 in the positioning ring I5,

In installing the lamp IE], it is first rotated until the positioning lug 38 and its right-angled projection 4| com-e into alignment with the slot 39 in the ring I5. The lamp is then pushed upwardly until the projection 4| clears the upper surface of the positioning ring I5 after which the lamp isrotated in the proper direction until the vertical abutment surface of the positioning lug 38 abuts against the shoulder :40 inv the position: ing ring, thus causing the projection ;4I toover:

lie the positioning ring. The lampis then allowed to drop downuntil theprojection 4I rests on the positioning-ring, I 5, the projection 4 I thus serving as a retainin ledge for temporarily sup-j portinglthe lamp within thelamp housing II. With; thelamp Lthustemporarlly supported within. the lamphousing, the bottom closure cap I8 canthen .be-convenientlythreadedinto placein the socket body I3, the spring contact 22 of the closure, cap forcing the lamp upwardly until the upper. surface 31 of the positioning -flange.35;on

the lamp, base, engages the under surface; I tj-of. The lamp is .thenpin, proper assembled position within the lamp hous-r ing II with the filament 30 ,in, a, predetermined;

the positioning ringy- I5.

position therein. The positioning lug 38 and its right-angled projection? thus serve as engagement means for temporarily supporting the lamp enable1the grasping of the cylindrical side ofthe lamp base -shell for lamp removal purposes,;.I-

the lampgbase preferably; intheform of lateral ussprcxte sio s 41 n1t e-:basee 48 Q t e amp. e ishown in Fig.- 67,- Smhluss orw s provide a ready fingergripen,thelamp base and thus facilitateithe removal of the lamp from the socket. Alternatively,- the finger grip means. on

therlamp base may be constituted suitable extrusions punched in or otherwiseformed on the lowerendpf, the baseshelli32, x u l y .QWhat-J claim;:.as new and desire-to secure by- Letters; Patent ofthe United States is: I

e e t i la pc p s n a bulb, a li ht source, within said-bulb, and, a baseesecured to said bulb, and :having; laterally projecting flange means for engagement with the bottom surface of, acooperating slotted ring in a socket; said base within the socket as well as for positioning the lamp in a definite angular position therein.

In the modification shown in Fig. 4, the prefocusing collar 34 is provided with a pair of lugs 42, 43 extending laterally outward from the sleeve portion 35 of the collar and circumferentially spaced thereon, the said spacing of the lugs, however, being somewhat less than the width of the slot 39 in the positioning ring so that both the lugs can freely pass through the slot at the same time. The lugs 42, 43 are also vertically spaced, i. e., they are spaced axially of the sleeve portion 35. The lower lug 42 serves as the angular positioning means for the lamp while the upper lug 43 serves as the temporary support means for the lamp. The arrangement of the two lugs 42,

43 is preferably such that when the lower lug 42 l is in engagement with the shoulder 40 in the positioning ring I to thereby angularly position the lamp about its axis, the upper lug 43 will overlie the ring I5 rather thanthe slot 39. In this manner, the upper lug 43 will engage the ring I5 and support the lampwithin the housing II when the bottom closurecap I8 is unthreaded from the socket body I3. The two lugs 42, 43 are preferablyformed. out of the material of the sleeve portion 36 of the prefocusing. collar; but if desired, they may be formed as I separate members suitably secured to the collar.

, In the modification shown in Fig. 5, the positioning flange 35 of the prefocusing collar 34 is provided, at its periphery, with an upstanding lug 44 having a notch 45 formed in one of itsradial sides at the lower end thereof and providing a retaining ledge or shoulder 48. Thenotch 45 exhaving engagement means at the upper side of said flange means with a portion arranged to pass through the slotted portion of said ring and engage the uppersurface thereof to temporarily I support the lamp in the socket, and with another portion arranged to engage a side of the slot in the ring for positioning the lamp in a definite angular position within the socket.

2. An electric lamp comprising a bulb, a light source withinsaid bulb, and a base secured to said bulb and havinglaterally projecting flange means for engagement with the bottom surface of a cooperating slotted ring in a socket, said base having lug means at the upper side of said flange arranged to pass through the slotted portion of said socket ring and providing a vertical abutment surface for angularly positioning the lamp within the socket by engagement with the side of the slot in the ring, and a downwardly facing engagement surface for temporarily supporting the lamp within the socket by engagement with the V and another portion providing a downwardly factends upwardly from the upper surface 31 of the positioning flange 35 and is of suiiicient vertical extent to permit the entry; thereinto of the shoulder 40 in the positioning ring I 5. The notch is preferably formed in that side of the lug 44 which is moved towards the shoulder 40 in the positioning ring I5 as the bottom closure cap I8 is threaded into the socket body I3. The retaining shoulder 48 formed by the notch 45 serves as the preliminary support means for the lamp, the said shoulder restin on the upper surface of the positioning ring I5 and so supporting the lamp within the housing II while the bottom closure cap I8 is screwed into place in the socket body.

Inasmuch as the clearance between the socket and the lamp base isusually insufficient, in those commercial projectors employing the above described lamp mounting arrangement, to permit insertion of an operators fingers therebetween to mg engagement surface for temporarily supporting the lamp within the socket. u

4. In combination, an electric lamp socket comprising a tubular body portion and a positioning ring mounted therein transversely of the axis of said tubular body portion, said ring having aslot in its inner periphery extending parallel to the axis of said ring from one side of said ring to the other side. thereof, and an electric-lamp for in sertion into said socket and comprising a bulb, a

light source within said bulb, and a base secured to said bulb and adapted to be inserted into said positioning ring, said base having laterally projecting flange means for engagement with said positioning ring, and engagement means on said base adapted to pass through the said slot in said ring and having a portion arranged to engage the upper surface of said ring to thereby temporarily supportthe lamp within the socket and another portion arranged to engage a side wall of said slot to thereby position the lamp angularly of its axis within the socket.

5. A prefocusing collar for attachment to the with an upstanding sleeve portion', andmeansoni said sleeve portion disposed above said flange for temporarilysupporting and for angularly positioning the electric lamp within its socket,= said means comprising a lug having'a portion providing a vertical lamp positioning surface extending parallel to the axis of said sleeve and another portion providing a'lamp supporting surface facing said positioning flange.

6. A prefocusing collar for attachment to-the base of an electric lamp comprising a flat positioning flange provided at its inner periphery with a sleeve portion, and a lug. extending upwardly from the outer periphery-of said flange and providedat its lower extremity with a notch in one of its radial sides.

.7. In combination, an electric-lamp socket combaseof' an electric lamp comprisinga flat posisaid ring and to permit rotation of said base relative to said ring, said-engagement means having a portion arranged to engage theupper surface of said ring, upon rotationof said base, to thereby temporarily support the lamp 'within the socket andanother portion arranged-to engage a side wall of the slotted portion of the. ring to thereby position the lamp angularly within the socket.

FRANK E. CARLSON. 

